Using SDR-35 for Patio Drains

House Repair Talk

Help Support House Repair Talk:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.


Sep 9, 2021
Reaction score
Preparing to have a patio/sundeck put in using pavers. The house will have three rain gutter downspouts that would empty onto the pavers. Therefore, I want to place some 3" id SDR-35 pipe below the downspouts to collect the water and run it out to the curb. The most interior down spout drain/catch will be a 42 ft run.
The other two drains/catches are located 15 ft to the left of the 42 ft run pipe (running perpendicular to this first pipe). I am proposing to run the lower of these two side drain/catches 15 ft straight across to the 42 ft pipe and use a tee or offset tee connector to tie-in.
For the third drain catch being located slightly higher that second, I'd like to save some money on the overall pipe cost and run it diagonally to tie into the second drain pipe using an offset tee.
Is this typical, or do both runs from the side have to connect to the main drain on their own connections.
Thank you in advance,


  • 230504 Downspout Catch-Drains.pdf
    12.6 KB · Views: 1
I appreciate the response. Yes, the pipe will be underground (below the pavers.)
Thank you.
I did the same thing with 3" PVC - but I had an 80-foot run out to the curb. Worse, I had only 18" drop for the distance. I knew it might not work well. but decided it was worth trying out. If it failed I could just put the downspouts back where they were. Sadly, it can't keep up with heavy rain, but helps the big picture.
Be careful some municipalities will not allow this . I heard that one homeowner did this and the water Was sent to the street and then froze causing an accident that ended up in court.